Hammer CLI

We need easier way to add custom option sources and validations.
In both the ordering matters so we need to be able to specify where the operation should happen.

Example of block that should add option source resolving custom option right after resulution
of decumented options and doing some validation after all sources are done

class MyCommand

  evaluate_options do
    add_source(:after => :id_params, :source => CustomIdParams(self, :required_params => :object_id))
    add_source(:at => :start) { |defined_options, result| result.merge('option' => 'value') }
    add_validation(:at => :end) do
      any(:option_a, :option_b).required
    end
  end

  build_options
end